To engraft on any instrument a substantive exception not found in it, must be admitted to be a matter attended with great difficulty. And the difficulty increases with the importance of the instrument, and the magnitude and complexity of the interests involved in its construction. To allow this to be done with the Constitution, upon reasons purely political, renders its judicial interpretation impossible—because judicial tribunals, as such, cannot decide upon political considerations. Political reasons have not the requisite certainty to afford rules of juridical interpretation. They are different in different men. They are different in the same men at different times. And when a strict interpretation of the Constitution, according to the fixed rules which govern the interpretation of laws, is abandoned, and the theoretical opinions of individuals are allowed to control its meaning, we have no longer a Constitution; we are under the government of individual men, who for the time being have power to declare what the Constitution is, according to their own views of what it ought to mean. When such a method of interpretation of the Constitution obtains, in place of a republican Government, with limited and defined powers, we have a Government which is merely an exponent of the will of Congress; or what, in my opinion, would not be preferable, an exponent of the individual political opinions of the members of this court.
Dred Scott v. Sandford, 60 U.S. (19 How.) 393, 620-21 (1857) (Curtis, J., dissenting).